Sonu Sutradhar
Last Activity: 6 Years ago
As you have mentioned “USUAL 1 km WALK” so it should be kept in mind that the velocity of the person is constant.It is so because the person has a walk of 1 km very frequently or maybe regularly so his body muscles have attained a constant velocity for the path=1km through CONDITIONED REFLEX ACTION.
So it can be said that acceleration of the person(a)=dv/dt=0
We know,
F=ma
F=m*0=0
So the Average force of friction when a person has a usual walk of 1 km is ZERO